Treatment of infected and non-infected non-unions remain a major challenge after orthopedic fracture-related surgery. In clinical practice, several revision surgeries are usually required, including a radical debridement and exchange of implants, to control or even eradicate the infection to finally achieve bone healing. However, a clear treatment algorithm in clinical practice may be difficult to follow due to the heterogeneous patient population. Thus, so controlled settings for research purposes is better achieved in standardized animal studies. So far, there exists no multi-stage animal model that can be realistically transferred to the clinical situation in humans. The importance of such a model is obvious in order to be able to investigate different therapy concepts for infected and non-infected non unions. In 20 female Sprague-Dawley rats, a critical size defect by a femur osteotomy with 5 mm width was done. The periosteum at the fracture zone was cauterized proximal and distal to the osteotomy to achieve an hypovascularized situation. After randomization, 10 animals were intramedullary infected with a multisensible Staph. aureus strain (103 CFU). After 5 weeks, a second surgery was performed with removing the K-wire, debridement of the osteotomy-gap and re-osteosynthesis with an angle-stable plate. After further 8 weeks all rats were euthanized and underwent biomechanical testing to evaluate bone consolidation or delayed union, respectively. Additional micro-CT analysis, histological, and histomorphometric analysis were done to evaluate bone consolidation or delayed union, respectively, by the score of Lane and Sandhu and to quantify callus formation and the mineralized area of the callus.Aim
Methods
Between 2005 and 2012, 50 patients (23 female, 27 male) with
nonunion of the humeral shaft were included in this retrospective
study. The mean age was 51.3 years (14 to 88). The patients had
a mean of 1.5 prior operations ( All patients were assessed according to a specific risk score
in order to devise an optimal and individual therapy plan consistent
with the Diamond Concept. In 32 cases (64%), a change in the osteosynthesis
to an angular stable locking compression plate was performed. According
to the individual risk an additional bone graft and/or bone morphogenetic
protein-7 (BMP-7) were applied. A successful consolidation of the nonunion was observed in 37
cases (80.4%) with a median healing time of six months (IQR 6).
Younger patients showed significantly better consolidation. Four
patients were lost to follow-up. Revision was necessary in a total
of eight (16%) cases. In the initial treatment, intramedullary nailing
was most common. Methods
Results
